In fluidized-bed vessels such as those used in catalytic cracking, gasification, combustion, polymerization, and drying, there is a tendency for particles to agglomerate (i.e., to stick or fuse together to form larger masses) and deposit on top of and/or around the gas distribution grid inside the vessel.
Such agglomeration and/or accumulation can block the flow of the fluidizing gas. When the fluidizing gas flow is blocked, the fluidized bed can become unstable and collapse. In which case, the vessel would have to be shut down and cleaned. Also, when temperature sensors near the grid behave abnormally, the vessel would typically have to be shut down as well. Frequent vessel shutdowns are undesirable as they can delay production and increase the cost of running the vessel. Thus, there is a need to prevent or reduce agglomeration and/or accumulation on top of and/or around the gas distribution grid in a fluidized-bed vessel.
The present invention provides a solution for solving this problem.